Updated to 1.12!
You can't reserve battles, the first one who is online with an admin/mod and champion will get to fight.
... I think he is trying to avoid me. I come on the server say Yes! (He already knows I wish to challenge him) and he leaves. http://gyazo.com/bf297bf0b358831163818a2ff9b8fafa
lol, that happened to me with Noivern but now I got the badge from gavin lol